#81AFE3

CSS

:root {
  --high-seas: #81afe3;
  --high-seas-rgb: 129 175 227;
  --high-seas-oklch: oklch(0.741 0.09 252.1);
}

.element {
  color: var(--high-seas);
  background-color: hsl(212 64% 70%);
  border-color: oklch(0.741 0.09 252.1);
}

Tailwind CSS v4

@theme {
  --color-high-seas: #81afe3;
  --color-high-seas-50: #e4f7ff;
  --color-high-seas-100: #d4eaff;
  --color-high-seas-200: #bad7fb;
  --color-high-seas-300: #98bae5;
  --color-high-seas-400: #77a2d3;
  --color-high-seas-500: #5889c0;
  --color-high-seas-600: #4b74a2;
  --color-high-seas-700: #3c5d82;
  --color-high-seas-800: #294561;
  --color-high-seas-900: #1c2f44;
  --color-high-seas-950: #0c1c2c;
}

SCSS

$high-seas: #81afe3;
$high-seas-rgb: 129, 175, 227;
$high-seas-light: mix(#fff, $high-seas, 20%);
$high-seas-dark: mix(#000, $high-seas, 20%);

.element {
  color: $high-seas;
  box-shadow: 0 0 0 2px rgba($high-seas, 0.35);
}